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Re: column * row ??

  • To: mathgroup at smc.vnet.net
  • Subject: [mg28798] Re: [mg28791] column * row ??
  • From: BobHanlon at aol.com
  • Date: Sun, 13 May 2001 03:28:46 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

n = 5;
colvec = Table[ToExpression["a"<>ToString[k]], {k, n}];
rowvec = Table[ToExpression["b"<>ToString[k]], {k, n}];

Outer[Times, colvec, rowvec]

Bob Hanlon

In a message dated 2001/5/12 9:50:46 PM, jrchaff at mcn.net writes:

>Can someone tell me a way to mimic the building of
>an N x N matrix by multiplying a column vector
>on left times a row vector on right ? (both vectors
>of length N) - I mean in Mathematica, of course.
>
>i.e, want the result,
>
>(colvec){a1,a2, .. aN} * (rowvec){b1,b2,..bN} =
>
>result is matrix:
>
>{{a1*b1  a1*b2 .....  a1*bN},
> {a2*b1  a2*b2 .....  a2*bN},
>  ...     ...          ...  ,
> {aN*b1  aN*b2 .....  aN*bN}}
>
>
>When I try this in Mathematica all I can figure out
>how to produce is the standard dot-product.  If I
>try the 'transposed' lists/matrices, I get an error,
>even tho the product is defined by basic rules of
>matrix multiplication.
>


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